Not my thing, but interesting regardless.
I can only speculate what may bother people, but I have a couple of thoughts I can share.
The boobs seem close together, which isn't necessarily unrealistic, but the top looks to be convex. That's not something you conventionally get without push-up clothing, which she clearly isn't wearing. If you combine these two factors, it's easy to get the impression that something is wrong with the boobs. In addition, the side view seems to place them unnaturally high on the chest or else the chest looks stunted. The arms are held back to obscure the back, so it's hard to get a sense for the proportions of the torso.
Grafting the upper body of one creature to the lower body of another is notoriously hard to pull off, especially if the creatures are disproportionate in size. The scaly back you used to tie them together is a good method. I do see two major points of criticism with the point of transition that may put people off.
First, you are combining two creatures with completely opposed perceived standard stance. Humans, obviously, stand up straight by default with everything built tightly around a vertical skeleton with little horizontal footprint. The two-legged dinosaur that people usually imagine, on the other hand, is defined by a largely horizontal, more or less straight back around which everything is built, with legs the only necessary vertical element and a thick tail for counterbalance that follows the line of the back. As such you get a long default appearance. Overall, the model looks fairly short, more like a duck than a T-Rex. I imagine that clashes with people's preconceptions. It certainly does with me. If you look at a classical man/horse centaur you get the full length of the horse's body with a powerful human body to replace the neck which from a horse you know rises above the body. Putting an upright human body is not a problem because it's accepted that the spine has a bend in the right place and just keeps going up from there.
Your dinosaur doesn't have that. Where one would conventionally expect the spine to continue in a generally straight direction you have an almost right angle that could be seen as jarring and counter intuitive. Which ties in with the second point.
The transition from one creature to another may or may not require a visual trick to convince people that it looks proper. The aforementioned centaur has precious little trouble in the back, and the front is remarkably easy as well. Transitioning human abdominal muscle into the muscles of a horse's upper torso isn't a big deal since they are largely the same, mammalian muscles that have the added bonus of a bit of hair/fur to obscure the transition and any problems with it even more. Add to that that the human portion of a centaur is classically either well muscled or fat to match the bulk of a horse and you get a hybrid that flows together nicely.
In your case you have a slender human female and a bulky dinosaur that need to go together somehow. In the back, the aforementioned abrupt bend could be avoided with a more gently sloping transition that would make the model a little longer and suggest a line of the back more associated with a biped dinosaur. In the front, you have the bulging dinosaur body that pulls back into the female abdomen. There's also that belt-like bulge that I guess is your visual trick to tie them together. In my view this adds to the perception of an unnaturally short body and reinforces the idea that the bodies aren't merged and thus parts of the same creature but instead a torso simply stuck on top of another creature.
I think a more natural transition could be achieved if the torso was located further towards the front to enable a sloping back so that even though you have scales, the upper body looks upright from the rib cage on, or perhaps no less than a third thirds the length of the rib cage. On the front I'd remodel the human belly so slope similar to the back, going straight up from the belly button upwards and gently sloping back below it to transition into the dinosaur part. I would extend the dinosaur belly forward a little to tie into this and see that the sides slime sown on the dinosaur body rather than extend the human sides to get a matching width at the hip, since people are more aware of human anatomy and see distortions there more clearly than on a critter that's be extinct for millions of years, and finally rework the scaly belt to have a somewhat triangular shape that spans from the belly button down the sides to tie both creature halves together.
Hope this helps.
